ABSTRACT: Facies Variations in the Fish River Sequence

MYERS, MARK D., Division of Oil and Gas, State of AK, Anchorage, AK

Located in the Beaufort-Mackenzie basin, the Maastrichtian to Paleocene Fish River Group is interpreted as a type 1 depositional sequence consisting of: (1) a lowstand wedge (submarine canyon facies of the Cuesta Creek Member of the Tent Island Formation); (2) overlain by a transgressive systems tract (uppermost Cuesta Creek Member and the basal portion of the mudstone member of the Tent Island Formation); and (3) capped by a highstand systems tract (outer shelf, prodelta, and subaqueous delta plain deposits of the mudstone member of the Tent Island Formation, proximal delta front and delta plain deposits of the sandstone member of the Moose Channel Formation, and delta front and shelf deposits of the Ministicoog Member). This sequence unconformably overlies the Boundary Creek Formati n and is disconformably overlain by the Aklak Member of the Reindeer Formation.

From a petroleum exploration standpoint, a general deltaic depositional model is not sufficient to predict reservoir distribution within the Fish River sequence. For example, in outcrops in the Big Fish River area, the Moose Channel Formation is dominated by a progradational succession consisting of high bed load distributary channels and braided stream deposits. Although delta front deposits are present, they are relatively sand poor. In contrast, 20 km to the northeast along Eagle Creek, aggradational parasequence sets of sand-rich delta front deposits (stacked distributary mouth bars and sand-rich subaqueous delta plain storm deposits) are dominant.

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)